I am really curious about how the Blender normal improvement will work out.

I noticed with a different model that the shading artifact is there because of a rough geometry.
In general the NGON exporter for this shell works extremely flawless.
Just those corners have issues. As marked in the image adding more geometry and then also
moving the vertices so the flow / surface continuity is better extremely helps with removing
the shading artifact which in this case is simply because of some choppy and impossible to shade
smooth parts.

Michael is in such a situation it possible to have the side shells mesh as is but have more subdivision
along U or V of the edge rounding geometry so that the mesh flow between sides and edge is more
consisten?